leoswift9
Citan O2 sensor issues
Summary of the thread
A 2012 Mercedes Citan with a diesel engine was experiencing issues related to the O2 sensor, indicated by a check engine light and reduced fuel efficiency. The initial suspicion was a faulty O2 sensor or a catalytic converter issue. However, upon inspection, the problem was traced to a corroded plug connection in the wiring harness. Cleaning the connection and replacing the connector resolved the issue, restoring normal function and fuel efficiency.
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4 comment(s)
leoswift9 (community.author)
I'll check the wiring harness super closely tomorrow. When you say 'similar,' do you mean exactly the same symptoms – check engine light, fuel efficiency tanking, and O2 sensor code? Was it a pain to get to the wiring?
liamlion1
Yeah, pretty much the same. Light on, fuel consumption went up. I didn't mess with it myself, just took it to a workshop. They sorted it quickly. Might be worth doing the same, just to be safe.
leoswift9 (community.author)
Turns out you were spot on. I checked the wiring harness, and the plug connection was indeed corroded. I cleaned it up as best I could, but in the end, I took it to a local shop. They replaced the connector and did a diagnostic check. Total cost was 95€. Check engine light's gone, and the fuel efficiency seems to be back to normal. Fingers crossed it stays that way!
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MERCEDES
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CITAN
liamlion1
I had something similar happen on my Citan. Check the wiring harness connected to the O2 sensor. Is it visibly damaged or corroded? I'm not a mechanic, but that was the culprit for me. What's the error code?